Feeding your Inflaton: Non-Gaussian Signatures of Interaction Structure

Primordial non-Gaussianity is generated by interactions of the inflaton field, either self-interactions or couplings to other sectors. These two physically different mechanisms can lead to nearly indistinguishable bispectra of the equilateral type, but generate distinct patterns in the relative scaling of higher order moments. We illustrate these classes in a simple effective field theory framework where the flatness of the inflaton potential is protected by a softly broken shift symmetry. Since the distinctive difference between the two classes of interactions is the scaling of the moments, we investigate the implications for observables that depend on the series of moments. We obtain analytic expressions for the Minkowski functionals and the halo mass function for an arbitrary structure of moments, and use these to demonstrate how different classes of interactions might be distinguished observationally. Our analysis casts light on a number of theoretical issues, in particular we clarify the difference between the physics that keeps the distribution of fluctuations nearly Gaussian, and the physics that keeps the calculation under control.Comment: 33 pages (plus appendices), 3 figures. V2: references added, some minor clarifications. Accepted for publication in JCA

Biodiversity of echinoids and their epibionts around the Scotia Arc, Antarctica

The Scotia Are, linking the Magellan region with the Antarctic Peninsula, comprises young and old islands both near continents and isolated, and is the only semi-continuous link between cool temperate and Antarctic environments. It is an ideal region for studies on how marine biodiversity changes across an extended transition zone. Echinoids (sea urchins) and their associated epibionts were found across depths from 91-1045 m, with 19 species from shelf and four from slope depths. The 23 species from 38 trawls represent 31% of all echinoid species known from the Southern Ocean and 38% of the shelf/upper slope echinoids. The specimens collected comprise representatives of the five families Cidaridae, Echinidae, Temnopleuridae, Schizasteridae and Pourtalesiidae. Echinoids are probably a good model for how well we know Antarctic shelf and slope megabenthos; none of the species we report are new to science but we found nine (39%) of our study species present at new localities, some thousands of kilometres from previous findings. New biogeographic ranges are illustrated for Ctenocidaris gigantea, C. nutrix, C. spinosa, Abatus curvidens, A. ingens, A. shackletoni, Amphineustes rostratus, Tripylaster philippi and Pourtalesia aurorae. Southern Ocean echinoids show eurybathy as the mean depth range of our study species was 1241 m and only one was at less than 500 m. The current view of echinoid dominance of super-abundance in the shallows seems to be not transferable to shelf and slope depths as only one of 38 trawls was dominated by echinoids. Current knowledge on maximum sizes in Antarctic echinoids seems to be good as our morphometric measurements were mainly within known size ranges. Regular echinoids increased predictably in mass with increasing test length, apart from Ctenocidaris spinosa. Tissue mass of cidaroid species was similar to 17%, but across irregular species varied from 17.7-8.9%. No epibionts were found on irregular echinoids or Echinidae but 70 cidaroids examined carried 51 species representing ten classes. Many of these species are reported as cidaroid epibionts for the first time. Cidaroids and their epibionts constituted > 38% of the total macrofaunal richness in the trawls they were present in. Echinoids and their epibionts clearly contribute significantly to Southern Ocean biodiversity but are minor components of biomass except in the shallows

Vehicle effects on the in vitro penetration of testosterone through equine skin

The effects of three vehicles, phosphate-buffered saline (PBS), ethanol (50% in PBS w/w) and propylene glycol (50% in PBS w/w) on in vitro transdermal penetration of testosterone was investigated in the horse. Skin was harvested from the thorax of five Thoroughbred horses after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into Franz-type diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of testosterone, containing trace amounts of radiolabelled [C-14]testosterone, in each vehicle were applied to the outer (stratum corneum) surface of each skin sample and aliquots of receptor fluid were collected at 0, 2, 4, 8, 16, 20, 22 and 24 h and analysed for testosterone by scintillation counting. The maximum flux (J(max)) of testosterone was significantly higher for all sites when testosterone was dissolved in a vehicle containing 50% ethanol or 50% propylene glycol, compared to PBS. In contrast, higher residues of testosterone were found remaining within the skin when PBS was used as a vehicle. This study shows that variability in clinical response to testosterone could be expected with formulation design